Railway traffic controlling apparatus



Sept. 6, 1932. MQQANN 1,875,877

RAILWAY TRAFFIC CONTROLLING APPARATUS Original Filed March 4 L931 Xi II IN VEN TOR.

# 4 ATTORNEY.

R-Pr- M; Can/ Patented Sept. 6, 1932 1 UNITED STA TES PATENT nonALn A. MCCANN, 0F SWISSVALE, rnnnssrnvnninnssrenon To THE Union swrren & SIGNAL COTEPANY, OF SWISSVALE, PENNSYLVANIA,

SYLVANIA.

, RAILWAY TRAFFIC CONTROLLING APPARATUS Application filed March 4, 1931, Serial No. 519,986. Renewed December 2, 1931.

My invention relates to railway traffic conrolling apparatus, and particularly to automatic train control or cab signal'systems of the continuous inductive type. More spe- '5 cifically my present invention relates to the trackway portion of such systems.

1 will describe one form of trackway apparatus embodying mylnvention, and will then point out the novel features thereof in 10? claims.

The accompanying drawing is a diagram matic view showing-one form of-trackway apparatus embodying my invention.

Referring to the drawing, the reference 11 characters 1 and 1 designate, the track rails of a stretch of electric railway track along which trafiic normally moves in the direction indicated by the arrow. These rails are divided by insulated joints 2, to form a plurality of track sections, of which only one section C-D is shown in the drawing, and the usual impedance bonds 18 are provided to con-- duct the propulsion current around the nsu-- at times energized as hereinafter explained.

V Locatedadjacent the exit end of the track section CD is a track transformer F, the secondary 8 of which is connected across the track rails, and the primary 9 of which is at relay G is from terminal 13 of a suitable source times energized as hereinafter explained.

The track relay E controls a coding relay G in such manner that the coding relayis energized when and only when front contact 7 of relay E is closed. The circuit for the of curren through contact 7 of relay E and the winding of relay G to terminal 0 of the same SOl'iI'CG Of current.

he coding relay G controls a coding device H, which device comprises, an operating winding 14, and two contacts 15'and 16 which are periodically closed at different rates when A oonrona rron or rnnnthe winding 14: is energized. The circuit for winding 14 of the coding device" His from terminal X through back contact'12 of re lay G, and the winding 14 to terminal Y; It follows that the coding device H is normally'de'energized, but is set into operation when thecoding relay G becomes deenergized;

When the codingrelay G is energized, the primary 9 of transformer F and the stator winding 5 of relay E are both supplied with uninterrupted alternating current of normal voltage, such, for example, as 110 volts. The circuit for the transformer primary is from terminal X of a suitable source of alternating current, through the front point of contact 10 of relay G, and the primary 9 of trans former F to terminal Y of the same source. The relay winding 5 is connected in multiple with the transformer winding 9 in this cir-' cuit. i

Interposed between the transformer secondary'8 and the track rail 1, is the primary of an auxiliary transformer Z. The secondary of this transformer Z is connected with the input terminals of a full wave rectifier W, and the output terminals of this rectifier'are connected with an auxiliary relay K through a back contact 13 of relay G. The relay K is so adjusted that it is normally open, and that when a train moving toward the right passes through section CD, this relay will not close until the train reaches theexit endof the sec tion. I

When the section C-D is unoccupied, track relay E is energized by current oflnormal voltage in both of its windings, so that relay G is energized, and the parts arein the conditions in which'theyare shown in the draw-.

ing. When a train moving toward the right enters section CD, itwill deenergize relay E thereby opening the circuit for the cod-.

ing relay G at contact 7. The circuits pre viously traced for the primary 9 of transformer F and the winding 5 of relay'E will then be opened at the front point of contact 10 of relay G, and anew circuit for these 7 elements will be closed at the back point of the same contact. The circuit for transformer primary 9 will then be from term'inal X through back contact 11 of relay G,- back point Y. The relay winding 5 is connected in multiple with primary 9 as be fore. The voltage which is thus supplied to primary 9and winding 5, is I lower than normal, and may, for example, be 80 volts. The current thus supplied to these elements will be periodicallyinterrupted at one rate or another by contact 15 or 16 of the coding deviceI-I, according as track relay'E is energized or deenergized, that is, accord ing as the section in advance of section C-D is unoccupied or occupied. 7 When the train approaches the exit end of section CD, the current supplied to the auxiliaryrelay K will become sufiicient to close this relay, thereby opening back point ;of contact 20 an closing the front point of this contact. This will open the circuits just traced for elements 9 and 5, and will close a new circuit for these elements, Which circuit is from terminal X through the front point of contact 20 ofrelay K, contact 15 or 16 of the coding device H, front or back point of Contact 17 of relay E and the backpoint of contact 10 of relay G to the elements-9 and 5. The current thus applied to the elements 9 and 5 will be at a higher voltage than before the operation of relay K, and the new voltagemay, for example, be 125 volts. WVhen the trainpasses out .of section C--D,' track relay E will become energized, and this will cause the coding relay G'to become energized, thereby opening the circuit for the auxiliary relay K. The partswill then be restored to the conditions in which they are shown in the drawing. c

In systems of the character described, it has been customary to supply uninterrupted alternatingcurrent at 110 volts to the primary 9 and track relay winding 5 when the section is-unoccupied, and to supply periodically in terrupted current at the same voltage to these elements when the section is occupied by a train.' It has been found that under these conditions the train-carried apparatus which responds to the periodically interrupted or coded current in the track rails may be energizedto an excessive value, and it has also been found that this over energ1zat1on reduces the sensitivity of the train-carried ap paratus is so far as concerns the detecting of a broken rail. That is to say, should one of the rails of section CD be broken, the socalled sneak currents through the impedance bonds, the crossbonding between-rails,

and the unbroken rail, may be sufilcient to falsely energize the apparatus on'a 'train'occupying this section. In accordance with my invention, the amount of current applied to the track rails by the transformer F when the section is occupied, is reduced to such a value that it will satisfactorily operate the traincarried apparatus under normal conditions, but that in the event of a broken rail the sneak currents will not be of sufficient value to falsely energize the apparatus on the train, whereas when the train is about to leave the section, the voltage is again raisedto such valuethat the track relay will immediately become effectively energized as soonasthe section'is vacated.

Although I have herein shown and de scribed only one form of apparatus embodying my invention, it is understood that va rious changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

, Having thus described my invention, what I claim is: r

1. In combination, a section of railway track,'a centrifugal track relay for said sectionhaving two windings the first of which is connected across the rails at the entrance endof the section, a normally energized approach relay having a circuit controlled by a front contact of said track relay, a track transformer having its secondary connected across the rails atthe exitendof said section through the primary of an auxiliary transformer, an auxiliary relay supplied with current from the secondary of said auxiliary transformer through a back contact of said approach relay and arranged to remain open whenthe section is occupied until the train approaches the exit end of the section, means 7 operating when said approach relay is energized to supply uninterrupted alternating currents at normal voltage to the primary of said track transformer and to the second Winding of said trackrelay, means operating.

when said approach relay is deenergized and said auxiliary relayis open to supply periodically interrupted alternating current at a voltage below normal to the primary of said track transformer and to thesecond winding of said track relay, and means operating when said approach relay is deenergized and said auxiliary relay is closed to again increase the voltage at which current is supplied to said track transformer primary and the second winding of the track-relay.

2. In combination, a section of railway track, tion having two windings the first of which is connected across the rails at the entrance end, of said section, means operatingwhen a centrifugal track relay for said sec current at reduced voltage to the rails and to said second relay winding, and means responding to the increased current drawn as the train approaches the exit end of the section for again increasing the voltage applied to the rails and to the second relay winding.

3. In combination, a section of railway track, a track relay having a winding connected across the rails at the entrance end of said section, a track transformer having its secondary connected across the rails at the exit end of said section through the primary of an auxiliary transformer, an aux iliary relay supplied with current from the secondary of said auxiliary transformer and arranged to remain open when the section is occupied until the train approaches the exit end of the section, means operating when said track relay is energized to supply uninterrupted alternating current at normal voltage to the primary of said track transformer, means operating when said track relay becomes deenergized due to the entrance of a train into said section to supply periodically interrupted alternating current to the primary of said track transformer, and means controlled by'said auxiliary relay for varying the voltage at which periodically interrupted current is supplied to the primary of said track transformer.

l. In combination, a section of railway track, a track relay having a winding connected with the rails at the entrance end of said section, means operating when said relay is energized to supply current of one volt age to the rails of the section, means responsive to the deenergization of said relay to reduce the voltage of the current supplied to the rails of said section, and means operating when a train approaches the exit end of said section to again increase the voltage applied to the track rails.

5. In combination, a section of railway track, a track relay having a winding connected with the rails at the entrance end of said section, means operating when said relay is energized to supply uninterrupted alternating current at normal voltage to the rails at the exit end of said section, means responsive to the deenergization of said relay to supply periodically interrupted alternating current at a lower voltage to the rails at the exit end of said section, and means operating when a train approaches the exit end of said section to again increase the Voltage applied to the rails.

6. In combination, a section of railway track, a track relay having a winding con nected with the rails at the entrance end of said section, a track transformer having its secondary connected with the rails at the exit end of saic section through the primary of an auxiliary transformer, a normally energized approach relay having a circuit controlled by a front contact of said track relay, an auxili'ary relayzsuppliedwith current from the secondary of said auxiliary" transformer to a back contact ofusai'd approach relay and arranged to remain open when'the section is occupied bya train until the train; approaches the exit end of the section, means'oper'ating when said. approachrelay is energized to sup-. plyiuninterrupted alternatingcurrcnt at normalt volt-ageito' the primary of said track transformer, means operating'when said approachrelay is deenergized and. said auxil iary relay is open to supply periodically interrupted alternating current at a low'er'voltage to the primary of saidtrack transformer, and meansoperating whensaidapproach re lay is deenergized and said auxiliary .re lay is closed toagain increase the voltage at which current is supplied to said track transformer. V -a i f 7i A trackcircuit system including; a sec tionof railway track,.a normally closed track circuit including a relay and a source ofcurrent that is connected to the track as long as said relay holds a front contact closed, said relay being deenergized upontheentry of a train into the section, and means so controlled by the relay when-deenergized: and by the trainthat when the latter has advanced'a-dis tance within the limits of a section a source of current is connected to the track of such character as to energize, after;the train has left thesection, said relay to close its front contact.v ,j

8. A track circuitsystem including: a section of railway track, a normally closed track: circuit including a relay and a source ofcurrent that is connected to the track as long as said relay holds a' front contact closed, said relay being deenergized upon the entry of a train into the section, and meansso controlled by the relay when deenergized and by the train that whenthe; latter'nears the end of the section, but beforeyleaving it, a source of current is connected to the track of such character as to energize,after the train has left the section, said relay to close its front contact. c

9. A track circuit system including: a section of railway track, a track relay, means I controlled by the track relay to normally supply current to the track ofa character sufficient to energize the track relay, means operating when the track relay becomes deenergized to supply to said track a train-control current of a character differentfrom, and in place of, the current normally supplied to the track, and means, controlled by the train as it advances within the limits of the section, to supply to the track, while the train is still in the section, current of a character to energize the track relay after the train leaves the section.

' 10. A track circuit system including: a seo- I tion of railway track, a track relay, means controlled by the track relay to normally suptrack relay after the train leaves the section. a 11. A track circuit system including: a c

ply current tothe track of avoltage sufficient to energize the track relay, means operating whenthe track relay becomes deenergized to supply to said track a train control current of a'lesser voltage in place of thecurrent normallysupplied to the track, and means, controlled by the train as it advances within the limits of the section, to supply to the track, while the train is still in the section, current of a voltage sufliciently high to energize the section of railway track, a track relay, means controlled by the track relay to normally supply current to the track of a character sufficient to energize the track relay, means operating whenthe track relay becomes deenergized to supply to said track a train control currentof a character different from, and in place of, the current normally supplied to the track, and means, controlled by the train as it advances within the limits of thesection,

' to supply to the track, while the train is still in the section, a train control current of a character to also energize the track relay after the train leaves the section.

12. A track circuit system including: a section of railway track, a track'relay, means controlled by the track relay to normally supply current to the track of a voltage sufficient to energize the track relay, means operating when the track relay becomes deenergized to supply to said track a train control currentof a lesser voltage in place of the current normally supplied to the track, and means, controlled by the train as it advances within the limits of the section, to supply to the track, while the train is still in the section, a train control current of a voltage sufliciently high to energize the track relay after the train leaves the section.

In testimony whereof I afiix my signature.

RONALD 'A. MGGANN. 

